For improved accuracy under such conditions,
the GPI flow computer allows for "field" calibra-
tion, that is, user entry of custom calibration
parameters. A "single point" calibration may
yield acceptable accuracy in the middle of the
flow range, but five or more calibration points
may yield a higher level of accuracy, especially
at the lower end of the flow range. Up to 15
custom calibration points can be entered.
Dispense/Display Field
Calibration Procedures
1. Hold down CALIBRATE while pressing and
releasing DISPLAY until the field calibra-
tion curve appears ("CAL B" message will
be displayed). Release both buttons.
2. To calibrate, press and hold the CALI-
BRATE button. While continuing to hold
CALIBRATE, also press and hold the DIS-
PLAY button. Hold both buttons for about
3 seconds until you see a blinking "dd CAL"
message. Once the "dd CAL" message
appears, release both buttons. You are
now in field calibration mode.
3. Once the buttons have been released from
Step 2, the display will show the blinking
message "run 01". If you want to exit the
calibration now before dispensing any fluid,
go to Step 11.
4. If you want to continue with the calibration,
but have not dispensed any fluid yet, make
your final preparations to your pumping
system, but don't start pumping yet.
5. Start your pumping system so that fluid
flows through the meter. The display will
stop blinking and show the "run 01" mes-
sage. Dispense into a container that allows
you to judge the amount of fluid pumped.
When you have pumped the desired amount
(for example, 10 gallons), stop the fluid flow
quickly.
6. Once the flow has stopped, briefly press
and release both buttons. At this point the
computer display will change to "0000.00"
with the left-hand digit blinking.
7. Enter the volume (amount) of fluid that you
dispensed (for example, if your 10-gallon
container is full, enter "10.0" for gallons or
"37.5" for litres). To enter numbers, use
the CALIBRATE button to change the value
of the digit that is blinking and use the
DISPLAY button to shift the "blink" to the
next digit.
8. Once the correct number is entered, briefly
press and release both buttons. The dis-
play will now change to a blinking "run 02"
message. You have installed the new cal-
curve point. You are ready to end calibra-
tion (Step 10) or enter another new calibra-
tion point (Step 9).
9. To enter another calibration point, go back
and repeat Steps 3 through 8. It is possible
to set up to 15 cal-curve points, and the
"run ##" message will increment each time
you repeat the calibration process (run 01,
run 02, run 03, etc., up to run 15).
10. To end calibration, press and hold both
buttons for about 3 seconds until you see
the "CAL End" message. After you release
the buttons the computer will resume nor-
mal operations with the new cal point(s)
active.
11. If you HAVE NOT dispensed any fluid, you
can exit calibration without changing the
cal curve. If the message "run 01" is show-
ing and you have not dispensed any fluid,
hold both buttons for about 3 seconds until
you see a "CAL End" message. After you
release the buttons, the computer will re-
sume normal operation and the old curve (if
you entered one in the past) is still intact.
Calibration with Conditioned
Signal Output Module
The K-factor of your meter appears on the
calibration report as the number of pulses per
gallon. The factor is determined during produc-
tion using water at 70°F (21°C). This K-factor
may be used for "single point" calibration and
provide acceptable accuracy. However, read-
ings may not be accurate when using this
calibration method in some situations. One
example is when using the meter under ex-
treme temperature conditions or with fluids
other than water.
For improved accuracy under such conditions,
we recommend that a K-factor specific to the
application be determined and used for cali-
bration. A "single point" calibration may yield
acceptable accuracy in the middle of the flow
range, but five or more calibration points may
yield a high level of accuracy, especially at the
lower end of the flow range.
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